Yahoo Chief's Audience Left Cold by Late Arrival

For media companies, the Cannes advertising festival is all about getting face time with top media buyers and advertisers. Yahoo Inc. Chief Executive Marissa Mayer missed a golden opportunity to do just that last week.

Last Tuesday evening, Interpublic Group of Cos. arranged a dinner at the swanky French Riviera restaurant L'Oasis for Ms. Mayer to meet executives from marketers such as Mondelez International Inc., brewer MillerCoors...